In the last decade, anterior temporal lobectomy (ATL) has become a widely-used treatment for epileptic patients with intractable partial seizures of temporal lobe origin, and recent studies have shown that approximately 70-80 percent of properly selected patients can be rendered seizure-free after surgery. However, the promise of seizure freedom often must be weighed against the risk of memory or language disorder resulting from resection of functional brain tissue. Mesial temporal lobe structures, from which epileptic seizures commonly originate, are crucial for the acquisition of new material into memory. Resection of the medial temporal region during standard ATL can lead to post-surgical memory impairments, particularly after dominant hemisphere resection, and particularly in patients whose preoperative neuropsychological testing suggests a functionally intact memory system. Because of this, development of noninvasive methods capable of assessing functional adequacy of the medial temporal memory system and predicting neuropsychological morbidity after surgery are critical in maintaining a favorable risk-benefit ratio. The current proposal will initiate a series of studies designed to activate relevant structure within the medial temporal lobe using two memory tasks, and to measure such activation with functional magnetic resonance imaging. The short-term goal is to develop clinically useful protocols that can non-invasively map the function of relevant brain regions in surgical epilepsy patients for purposes of presurgically evaluating localization and functional integrity of the proposed resection zone. the long-term goal is to utilize results of these investigations to inform and constrain models of memory representation in the medial temporal lobe, specifically to assist in more precisely understanding the role of the hippocampus in human memory.